1. Field of the Invention
The present invention relates to a friction clutch device used for vehicles principally such as automobiles, motorcycles, etc. which clutch is engaged by applying a pressing force to a friction plate in a fixed direction and disengaged position by releasing the pressing force.
2. Description of the Prior Art
Conventional means for applying pressing force to the friction plate, in the friction clutch device as described above, include the type which uses a spring and the type which uses a hydraulic device. In the former type, to disengage the clutch, a force capable of overcoming the force of the spring is required. If the spring force is increased to increase the load capacity of the clutch device, the force to disengage the clutch becomes heavy. Because of this, this type has a disadvantage in that the disengaging operation cannot be achieved lightly. On the other hand, in the hydraulic type, there is a disadvantage in that when an oil pressure of an oil pressure source is lost, the engaged position of the clutch device cannot be obtained. In such a case, inconveniences occur. For example, when the vehicle is parked, the engine is not effective as a brake. The engine cannot be started by pushing the vehicle.